Using equipment that you haven't been trained on is OK as long as you're careful and read the directions. Correct answer: B You should be always careful when working out with any equipment. However, when the equipment is new and you are not used to it you should pay more attention and follow the instructions.
O air-filled cavities that secrete mucus to keep the nose moist and remove bacteria.
I believe the answer is C
I hope you get it right and have a great day :)